Pea base rot

Symptoms are also known as pea blight. It mainly occurs at the seedling stage. Infestation of the seed caused a bad planting, and the stem base or root neck of the seedling turned brown to reddish-brown contraction and rot. Cotyledons produce a red-brown, near-circular lesion on the cotyledons. Infection of stem base and root and neck results in reddish-brown oval or elongated lesions. The posterior disease area gradually sag, and when it expands to the circumference of the stem, the diseased part shrinks or cracks, causing the seedlings to grow slowly, fold down or gradually wither. . When the humidity is high, light brown spider silk mold grows.

The pathogen Rhizoctonia solani Kuhn described the Rhizoctonia solani AG-4 mycelial fusion group, which belongs to the fungus Subgeronia spp. The seedlings do not produce spores and are mainly spread and propagated by mycelia. The primary mycelium was colorless, followed by yellow-brown, septum, and coarse 8-12 μm. The branches shrank at the base and the old mycelia often presented a series of barrel-shaped cells. Sclerotia are nearly spherical or amorphous, 0.1 to 0.5 mm, colorless or light brown to dark brown. The spores are nearly round and the size is 6-95-7 (μm). In addition, Pythium debaryanum Hesse said that Pythium debari, can also cause base rot.

The transmission route and onset conditions are wintering in the soil with mycelia or sclerotia and can be rotted in the soil for 2-3 years. Mycelium can directly invade the host and spread through water currents and agricultural tools. The germ development is suitable for temperature 24°C, maximum 40-42°C, lowest 13-15°C, and suitable pH 3-9.5. Seeding is too dense, the seedlings are not timely, the temperature is too high or the back-season cultivation is easy to induce the disease. The bacteria in addition to damage beans, but also infested melons, eggplant, cabbage, rape, cabbage and so on.

Control methods (1) Use cold-resistant varieties such as safflower peas, soft-inner 1 and pea seedlings (grass beetle). (2) Choose a well-drained, sunny site for seedlings, use disease-free soil as bed soil, if using old wow seedlings, bed soil should fully turn over the sun. (3) Apply compost made from Japanese enzyme bacteria. Appropriate lime is applied to adjust the pH of the soil from slightly acidic to neutral, and the lime application amount is determined according to the soil pH. Generally, 667 m2 of vegetable is applied to 100 kg. (4) Strengthen the management of seedbeds, do a good job of seedbed insulation, and prevent cold and cold currents from attacking. Under the premise of seedlings not being frozen during the day, as many ventilations as possible are needed to promote seedling growth and robustness, and disease resistance is strengthened. Watering seedbeds depends on soil moisture and weather conditions, and prevents flooding to prevent excessive moisture in the bed. (5) Advocate the application of transplanting blending agent, which has strong bactericidal power, and can promote the growth of plant roots and enhance resistance to adverse conditions. It can also be sprayed with 20% methyl-rhodium phosphate (Like) 1200 times or 36% thiophanate-methyl suspension 500 times, 5% Jinggangmycin 1500 times, 15% When the mixture of Rhizoctonia solani and Pythium occurs, it can be sprayed with 72.2% Preclosure 800 times solution and 50% Formamide WP 800 times, each m22-3L. According to the condition, the disease should be controlled 2-3 times every 7-10 days.